As a conventional general linear guide device, for example, the one shown in FIG. 8 is known.
As shown in FIG. 8, this linear guide bearing device is provided with a guide rail 101 which extends in the axial direction and a slider 102 which straddles the guide rail 101 in a manner able to move relatively to it in the axial direction.
The two side surfaces of the guide rail 101 are formed with rolling element rolling grooves 103 which extend in the axial direction. The slider body 102A of the slider 102 is formed at the inside surfaces of two sleeve parts 104 with rolling element rolling grooves 107 which face the rolling element rolling grooves 103. Further, between each two facing rolling element rolling grooves 103 and 107, as one example of the rolling elements, a large number of balls B are rollably loaded. Through rolling of these balls B, the slider 102 can move relative to the guide rail 101 on it in the axial direction.
Along with this movement, the balls B interposed between the guide rail 101 and slider 102 roll and move to the end parts of the slider 102, but to continuously make the slider 102 move in the axial direction, these balls B have to be endlessly circulated.
For this reason, the sleeve parts 104 of the slider body 102A are formed inside them with rolling element passages 108 which run through the axial direction, and the two ends of the slider body 102A are fastened with substantially U-shaped end caps 105 through for example screws 112 or other fastening means. The end caps 105 are formed with direction changing channels 106 bent in semi-arcuate shapes connecting the two rolling element rolling grooves 103 and 107 and the rolling element passages 108, whereby rolling element endless circulation raceways are formed. Note that, in FIG. 8, reference numeral ill indicates a side seal member (rubber seal material) fastened together with the end cap 105 to an end face of the slider body 102A via screws 112 etc., 110 indicates a tap hole for a screw 112 formed at an end face of the slider body 102A, 113 indicates a greasing nipple, and 114 indicates a bolt hole for fastening the guide rail 101.
Each side seal 111, like the end cap 105, is made a substantial U-shape and has an inner circumference which is made a sealing surface which slides against the guide rail 101. It is formed from a steel sheet on which rubber is bonded by baking.
In this regard, in a linear guide bearing device used for a mechanical apparatus such as a machine tool wherein swarf or other foreign matter is produced in the surroundings, the seal by the above-mentioned side seal member 111 alone is not sufficient and the lubrication conditions also become tougher, so in the past, as shown in FIG. 9, it has been proposed to arrange a plurality of lubricant feed members 115 between the side seal member 111 for preventing small foreign matter from entering inside of the slider 102 and the end cap 105 in the axial direction of the slider 102 and to attach to the outside surface and inside surface sides of the side seal member 111 in the axial direction steel protectors (hard seal members) 117 which like the end cap 105 are formed in substantially U-shapes and which remove large foreign matter or hard foreign matter.
Each lubricant feed member 115 is made of a porous resin in which lubricating oil is impregnated, so like the end cap 105 is formed in a substantially U-shape, has fastening rings 116 for insertion of screws 112 fit at the outsides of the two ends of the U-shape, and is provided with sliding parts (not shown) which slide against the rolling element rolling grooves 103 of the guide rail 101 to feed lubricant at the insides of the two ends of the U-shape.
In the above conventional linear guide bearing device, the side seal member 111 and lubricant feed members 115 are not complete in sealing ability and are insufficient as seals. Further, when arranging a plurality of lubricant feed members 115 in the axial direction of the slider 102, if the facing surfaces of the lubricant feed members 115 which adjoin each other in the axial direction are pressed together, the contact pressure of the sliding parts against the rolling element rolling grooves 103 of the guide rail 101 becomes weaker. This sometimes causes the problem of the rolling element rolling grooves 103 not being sufficiently supplied with lubricant. Further, the lengths of the fastening rings 116 in the axial direction are made longer than the thicknesses of the lubricant feed members 115 in the axial direction to provide clearances C between the lubricant feed members 115, so there is a possibility of swarf and other foreign matter which built up at the clearances C entering inside of the slider 102 and causing early wear or breakage.
Therefore, as shown in FIG. 10, a linear guide bearing device has been proposed which prevents the entry of foreign matter to the inside of the slider so as to prevent early wear and breakage (see Patent Document 1).
The linear guide bearing device described in Patent Document 1 includes, at each end part of the slider (in actuality, the end cap), lubricant feed members 115 and a plurality of seals with different seal performances in that order. The plurality of seals with different seal performances include soft seal members constituted by the rubber seal material 111, resin seal material 120, and felt seal 121 and hard seal members constituted by protectors 117 as illustrated.
Further, a linear guide device has also been proposed which, to seal the clearance formed between the guide rail and the slider, is provided with an under seal includes a plurality of seal plates stacked in a height direction of the guide rail (see Patent Document 2).
The linear guide device described in Patent Document 2, as shown in FIG. 11, seals the clearance 222 formed between the side surface parts 202a of the guide rail 202 and the inside side surface parts 204a of the slider 204 by the provision of an under seal 224 made of a plurality of seal plates 228 stacked in the height direction of the guide rail 202.